When All Else Fails (Destroy It All)
by MikaCheshire
Summary: The 'angel of hostility' is back in the Japan Branch after many years. Her close relationship with the King of Space and Time has always been suspicious to the Order, but it was her friendship with Shiro that kept her on good terms. And she's one of the few that knew of Satan's half-demon son, the one who inherited the blue flames. She now comes back to have some fun. Mephisto/OC
1. Chapter 1

**Chapter 1**

The town of True Cross Academy was silent in the dead of the night. Only some roamed the night, quietly and peacefully while the rest slept, blissfully unaware of what roamed around them. One individual in particular quietly lay in her thoughts.

Golden eyes gleamed from the moon's dim light as their owner scanned the large area surrounding the school. The bangs of her white hair blew in the slight breeze as the rest of her long hair stayed in its tight bun, showing off her pointed ears and the crystal earing that hung from one. She laid on her front, her feet up and kicking back lazily. A long, white fur-tufted tail wagged idly with the wind.

Placing a strawberry flavoured lollipop in her mouth, she hummed in curiosity. "It's been a while since I've come here. I wonder if Samael has anything interesting for me to do," she wondered aloud before crawling up and flipping off one of the high ledges of the school. "Maybe I should check out the new Pages sometime soon."

The white haired woman easily jumped down ledges until she found an opened window into the school and slipped in. She landed with a soft thump, crouching on the ground, careful not to make too much noise though she knew no one should be there anyways. The coast clear, she brought herself up and walked from the empty room into the equally empty hall. Her white tail swept back and forth behind her as she walked with a bounce in her step.

She would smile and poke with a sharp nailed finger at the green-eyed coal tar that floated by, sometimes even cooing at the tiny demons. Though they were not her dominions, her kin, she still found them adorable in their human world forms. Her kin were her sons, all of darkness. They roamed in the shadows, lurking and waiting to find humans to tempt. They were tempters, whispers, but also fantastic familiars if the human interested them. She had other kin as well that were called 'adopteds'. She was the only one to do this, because not only was she the Prince of Darkness, but also of Worth. Her adopts were demons that had been deemed worthless, useless, by their own kin. So she took them in, under her control.

Because of this nature, some in Gehenna thought lowly of her. But she didn't really care what they really thought of her because it gave her more credibility with the Order.

She thought absentmindedly as she fingered at the exorcist pin attached to the breast pocket of her jacket. Stopping in front of a window that overlooked the town, she looked out with a sombre expression.

"I'm so sorry, Shirō. I swear, my father will pay one day," she promised, golden eyes glistening from unshed tears. But she shook off the remorse and with a twirl of her fingers vanished into the shadows.

She silently emerged in the 'Faust' residence in the town, slinking through whatever shadows there were in the lit, colourful hallways. It had been awful amount of time since she had stepped into these halls, though it was only a small amount compared to her long life. The sound of video games is what drew her to a familiar room; one she knew would be filled with anything of Japanese culture; an otaku the owner was. Just the thought almost made her roll her eyes, though she couldn't supress her smile.

With her infamous silence and sneaking, she crept into the coloured, cluttered room, to watch the familiar purple-haired demon. As his green eyes were preoccupied with the game that he played, she continued her advance. The white-haired demoness crouched behind him, behind the large pillows on the ground that he laid on. And when a critical part in the game came, she interrupted him by putting her hands over his eyes and tugging him backwards. He gave a surprised grunt before falling against her, tightly gripping onto the game controller.

"'ello, _Mephisto_," she whispered into his ear before sliding her hands down and wrapping her arms around his neck. She nuzzled her face into the nape of is neck, having sorely missed her close friend.

And he knew who it was just by the feel of the hands that stole his sight and the smooth voice that spoke his false name. After years of separation, well, of _course_ she would choose to appear in such a way. She was always sneaky when it came to entrances. She wasn't flashy like him, but she certainly loved causing a good scare from it.

"Nice kimono," she commented, her arms letting go of him finally. Sitting back on her hunches, she proceeded to shed her soft leather jacket.

Mephisto turned his gaze from the TV screen to her, the curl on his head bobbing with the movement. He frowned. "You made me lose."

She shrugged as she folded the jacket and placed it on the ground next to her. "What a greeting," she said sarcastically. "And that's why there are checkpoints in games," she retorted. The demoness unravelled the cloth that was wrapped around her hips, previously holding one of her sheathed kukri knife. With that placed on the folded jacket, she added to the pile the holster that held her other kukri knife, which was clipped to her thigh.

Now only clad in her wife-beater, tanned trousers, and long socks (having taken off her boots earlier), she climbed over the pillows to his side. As he resumed the game, she settled back into the huge, plush pillows. Her tail waved in contentment as she smiled.

After a moment of silence between them, only the sound of the game playing, she spoke up. "So what have I been called here for?" she asked as her long-nailed finger traced the pictures on the pink kimono he wore.

"Our youngest brother has finally joined the school." He paused the game, looking at her again. "He's joined the cram school and plans to become an exorcist." He grinned at her as he told her this. She could hear that sly humour in his voice, that one she knew all too well.

"Is that so?" She leaned further into the pillows. "So Shiro's foster son, who inherited the blue flames, plans to beat Father? Amazing." She loved the turn of events; it made things interesting. "Tell me," she started, her tail lazily caressing his clothed leg, "what are your plans? Because I know you're planning something."

He smirked at her, green eyes locking with her gold. "How does becoming a teacher sound like, Belial?" He leaned towards her, clawed fingers hooking into the band that held her bun up and pulled. Her white hair fell to its natural length, well past her shoulders.

She let him card through her locks and leaned even closer to him. Belial grinned at his question, face centimetres away from his. "Sounds like it's worth the fun."

0000000000

"All right, before we finish, I have no last thing," Yukio told the class in front of him, adjusting his glasses. The pages silently hoped for no additional homework. "Tomorrow you'll be gaining another teacher that will help you with your training. She'll be teaching you information that is actually hard to gain. So I advise you to pay attention when she comes." The exorcists-in-training looked at him in interest. "Any questions before I end class?"

"_Who is she?"_

"_Is she from a different branch?"_

"_Is she hot?"_

"Sorry, but I'm not allowed to give her identity. And I'll ignore the last question. If that's all, class is dismissed. See you tomorrow."

0000000000

"So, who is she, Yukio?" Rin asked, looking over the current manga he was reading. The twins had come back from cram school and were finally settled back in their dorm room.

The younger of the two sighed and stopped what he was doing at his desk to turn towards the half-demon. "I really can't tell you, Rin."

"C'mon, please?" he pleaded, his tail lazily thumping against the bedside.

Rubbing his temple, he sighed again. "I'll only tell you one thing, but then you have to wait until tomorrow to find out."

He perked up at this. "Okay," he grinned.

Yukio turned back to his work and answered without looking back. "She's a close friend to Sir Pheles and was a good friend of Dad's."

Rin shot up in surprise, but banged his head on the low ceil above his head. After quietly swearing, he cradled her head and looked to his brother. "A friend of Dad's? _Really?_" His face slipped from joyful surprise to a mixture of doubt. "And Mephisto's?

"…_She better not be some clown too_," he mumbled after falling back into his bed.

* * *

**So…**

**I hate myself enough to make another story. This has actually been on my mind for over a year. I just gave up and decided to write it. Fuck it, because it's so rare to find a Mephisto/OC story. It's always yaoi. And while I like yaoi, I don't pair any from AoE. **

**Enjoy?**


	2. Chapter 2

**Chapter 2**

_The white-haired demoness heaved a heavy sigh, a defeated look marring her appealing features. Her face was carefully cradled in the palm of her hand as she sourly looked across the table from her. Shirō looked pleasantly amused by her discomfort and laughed when she let her hand slip and slammed her forehand into the table. _

"_Shut upp~" she whined, her voice cracking._

"_Belial, I never expected you to be bother by being _feared _by another," he said with a light chuckle. _

_She tilted her head to the side, cheek pressed into the hard wood, and looked up at him. She pouted, red-faced from being flustered. "I gained two wonderfully adorable half-brothers and _one of them is terrified of me_. How could I _not _be bothered by that? I know, it's because he received a temptaint at birth, but am I really _that_ scary?" she asked him, picking up her head enough to rest her chin against the wood. _

_The Paladin opened his mouth to answer, but was immediately interrupted._

"_Beriaru! __**(1)**__"_

_The demoness' mood immediately peaked at the sound of the little voice. Sitting up and turning towards the doorway, her face split into a large grin. "Rin~" she cooed as the four-year old attacked her legs with a hug. With ease, she grabbed him underneath his scrawny arms and lifted him up. Blue eyes sparkled at her as she hung him in mid-air. "Rin, it's Be-li-al~ Not Beriaru," she tried to correct him as she hugged him close and snuggled into him. _

_She childishly stuck her tongue out at the exorcist when she saw him smirk at her. Directing her attention back at the child in hand, she gave Rin a quick look-over. "You're growing so much! I bet you're getting stronger too!" She took the child and sat him on her lap. _

_He grinned at her. "Of course! I'm gonna be stronger than you and my old man!" he replied, puffing his chest up in pride. _

_Behind her joyful smile, she inwardly smirked at his words. When his true nature was awakened, there would be no doubt that he would be strong. "Of course, you will," she agreed with him with a soft look. Turning towards her friend, she asked, "Don't you agree?" _

_Father Fujimoto grinned at her, then at his son. "Stronger than you perhaps, but it will take him a long time to surpass me," he joked. She chuckled, shaking her head. _

"_Nu-uh! I'm definitely gonna beat you!" Rin tried to argue. _

_Stopping the childish argument that would happen between father and son, she stole his attention. "You know what to do with strength when you gain it, correct?" He looked at her with wide eyes, expecting her to answer. _

"_You use it to protect the things you love, Rin," Shirō finished for her. _

_She cynically thought of their words. For her to say this to Satan's son, being a demon, and given her status as a Demon King, it was honestly ridiculous. Demons used their power for personal gain or just for senseless, merciless acts. It was hypocritical of her to say things like this, but she knew they were needed for the process. Fujimoto planned to raise him as a human, Mephisto planned to use him as a 'weapon'. She knew Rin would never stay 'human', but for him to be aware of his use of power, to acknowledge his demon heart but not immerse himself in it, was needed if he had any chance – any chance against their father. _

"_Like protecting Yukio!" the child gave an example with a grin. _

_Belial smiled at him sweetly. "Exactly! And speaking of him, where is little Yukio?" _

_The dark-haired boy looked behind him and then back to her. "I'll go get him!" he told him before jumping off her lap and running out of the room._

_When she heard chuckling, she shot a 'shut-the-hell-up' look at her friend. And when he didn't stop, she huffed. "Seriously, what's so funny?" _

"_To think the King of Evil has a soft spot," he snickered. In the background Rin was heard talking loudly for his brother to join him. _

_She rolled her eyes at his words, though begrudging thought the same. Puffing her cheeks in frustration, she gave a playful glare. "Shut it. Did you know being with you gives me such an urge to have a smoke again because you can be so irritating. You're lucky seeing my little brothers calm me so much."_

_Their conversation lulled to a silence for a small moment as they waited for the twins. Belial propped her elbow on the table and held her chin in her palm. When her ears picked up the pitter-patter of their tiny feet, she looked to her friend. "I'm being moved to the African Branch soon. You better raise my brothers well." _

oOoOoOoOoOoOo

When he heard that _incessant,_ unfortunately familiar whistling, Yukio sighed. The moment he heard it, he knew she would try her very best to disrupt his paperwork when she appeared. It was only ten minutes before he would have to go the cram school class, with their new teacher.

But it seemed like she had come early for once.

The door opened and the well-known white-haired demoness came through, listening to the music through the earbuds in her ears. When her golden eyes locked on the younger exorcist, she flashed a sly grin at him. "Hello, _teacher_ Yukio," Belial mockingly greeted him with a shallow bow of her head.

"Hello, Miss Swartz. I see you already got back into your old habits," the younger Okumura said. He continued working on his papers, despite her obvious glance at his work. He was aware what was formulating in her mind but ignored it.

Leaning against the desk, she poked him light in the cheek, clicking her tongue. "Now, now; I've told you before to neither be so formal nor bother with that fake name when we're in private. Honestly," she said with fake dramatics, "I'll never understand you Japanese and your need for distancing." She gave a short laugh, smiling at the hard look he gave her. "Just _joking_. Calm down," the demon told him, waving her hand dismissively.

Knowing it be impossible to get rid of her now, he sighed. Massaging his temples, he asked, "How was the African branch? Or did you move again?" He decided to start a small, simple conversation with her.

Belial snorted. "I think you mean, did _they_ move me again?" she retorted. "The African branch was fun. Interesting missions at least," she said with a half-shrug. "And they moved me to the South American branch six months before I finally came back here. Not as fun." She grimaced before her eyes flitted over the room before looking back at him.

"What should I be expecting from these kids?"

"Many of them are smart," he answered, "but Rin tends to be the biggest problem. Other teachers say he doesn't really pay attention and learn. Sometimes the students get into arguments with one another."

She nodded, understanding. A grin lit up her face, pointed canines showing. "Should be fun, _interesting_. And how _is_ that trouble-making older brother of yours?"

Yukio slowly stood from his seat after finishing his work, answering her while doing so. "I suppose you'll find out in a few minutes, right?"

As he rounded the desk, she smirked, pointing out, "Deflecting my question, are you?" with a sharp nail finger, she tapped her chin in wonder. "Think he'll remember me? I mean, you mainly know me because of being an exorcist and sometimes visited the Branch here. Him, well, I haven't seen in _years_."

Checking the time, he realized it was close enough to go early. He motioned to the door and she easily followed. "Was the reason why you came back Rin's awakening?" he asked, looking forward as they walked.

She sadly smiled at the almost accusing tone. "Now, now; no need to get sceptical of me. I was specifically requested by Mephisto to come back to the Japan Branch. As to what he's doing, it's anybody's guess and you know it," she lied, pointing a finger at him. "Plus, I wanted to see my adorable half-brothers," she cooed.

Her light mood dropped as he didn't respond; in fact, it soured greatly. She grimaced, looking away. "Still not trustin' me, huh?" she quietly asked, enough for him to not hear.

oOoOoOoOoOoOo

"_Class, this is Bell Swartz, your newest instructor."_

_The class of pages looked in surprise at the woman in front of them. _

* * *

**(1) **_**In most languages, Belial stays Belial, so she's just used to it being pronounced that way. Beriaru is the Japanese Romanised version of her name.**_

**Wow, I was not expecting seven reviews already. Thanks, guys! :) **_** How do you think the class will react to their obviously demon teacher? **__**Andddd, should her demon status be immediately found out or later on? Opinions please? :)**_

**I had to completely re-write this because I hated the original chapter 2 I had started and almost finished. And sorry about the ridiculous wait. I lost all will to write because of this term. But! Since it's ending, I'm back in the mood. **

**Thank you!: **_**Dougall Dragon; Tachi Tsuki un; innocentrini; NyanVamp; Girlfriend101; AnonOfTheAnonymous; Guest; PhoenixBreaker90; near4EVER; The All Powerful Genie God; Fraijda the Music Freak; Mayumi Uchiha; Kilari G; Branabee; FullNight Alchemist; Shibien11; Lumina13; Her Extravaganza**_


	3. Chapter 3

**Chapter 3**

The class of pages was really overall silent as they waited for class to start. In the back sat the trio from the temple, two girls sat together to the side, two unsociable guys in the far back, and Satan's son sat in the front with the timid human girl he and his brother had helped earlier. They weren't a united class like Yukio had mentioned, only together with the one's they were friends with.

Most of their attentions snapped to the door when it opened and showed their current and newest teachers. Yukio walked to the front desk of the classroom and introduced the white-haired woman by his side. "Class, this is your newest teacher."

She was usually tall for a woman, just nearly the height of the young teacher beside her, and her body (Renzo couldn't help but comment on) was larger, curvier, but fit. She obviously avoided the True Cross Order uniform, wearing instead jeans and a loose, low-cut blouse with a soft leather jacket and knee-high boots. The only indication of her affiliation to the Order was the pin attached to the front of her jacket. Her white hair was pulled back into a bun again, showing off her pointed ears.

Maybe some would have been unnerved by the sharp gold eyes that watched them back, if not for the fur-tufted tail that lethargically swung behind her.

She was a _demon_, whether half or full was the question, and if full, how strong was she really to contain a human body?

"Hello, everyone," she greeted the class. "I am Bell Swartz, Upper First Class Exorcist. Your curriculum, it seems to me, has been rather lacking in Demonology, and who else but a demon to teach it, not to mention a high ranking one? I'm not criticizing your former instructor's knowledge, but truly, who can you see knowing more, a human or demon?"

"Why have you come now?" asked one of the male students, half-masked distrust heard in his voice.

Her golden gaze shifted from the general class to the specific student. "Hmm?" she briefly glanced at Yukio, silently asking for the student's name, before returning her stare at the blond-streaked male. "Mr Suguro, yes? I've been moving through branches, haven't been in Japan for a more temporary stay for a while. Mephisto has requested for my help in the cram school, so I obliged."

With a light smile, she added, "Anything else before we start?"

"What's your real name then? Whose kin are you, especially if you're high-ranking?" Izumo questioned her.

The older demon looked from Bon to the purple-haired girl, tilting her head before smugly smirking. "Now, why would I do something as boring as simply answering that? I'm here to teach you demonology, so let's see if you learn and how long it'll take for you to identify me with some few hints." She looked over the class once more, pausing a little longer on Satan's son, gold eyes locking with blue.

Rin blinked before surprise lit up his face. Her face, so familiar looking, finally clicked in his mind. He shot out from his seat, one hand flat against the desk surface in front of him as he used the other to point at her. "Wait a minute! Didn't you use to visit the church?"

Her shock broke her smug expression when he asked her this as she didn't except him to remember her from more than a decade ago. With a tilt of her head, and a heavy sigh sounding from Yukio beside her, a genuine smile spread across her face. "Yup. I was a friend of your father's. But we'll talk about that later, all right?" Rin grinned at her, nodding. She wasn't sure if he fully remembered her, but she decided to wait for after their classes were done.

Turning back to the younger of the Okumura twins, she lazily waved him away. "It's good. Don't worry about it. I'm sure I'll see ya after classes are down, m'kay?" Despite her words, he gave her an unconvinced look before leaving the class to her.

Once the door shut, she immediately started to teach. "Now, let's start with a simple review of what you _should_ know of. Now, there are nine of you, but some don't seem all that sociable. So, almost everyone, give me each one of the Baal, or the eight demon kings."

She started by picking one the student who had first talked to her. "Mr Suguro, if you may start for us."

"There's Iblis, the King of Fire."

She nodded, then picking on the picking his friends, asking their names beforehand.

"Beelzebub, the King of Insects." "Azazel, the King of Spirits."

She then turned her attention to the purple-haired student and her friend.

"Astaroth, the King of Rot." "Egyn, the King of Water."

In the front, she then turned to Rin and the girl near him. Smiling kindly at the timid blonde, she asked for her name.

"M-Moriyama Shiemi, a-and there's, um, Amaimon, the King of Earth."

Biting back a scowl from the mention of the demon's name, Belial gave a nod. "Yes, that's correct. Thank you, Miss Shiemi." Turning to Rin, she raised an eyebrow expectantly at the boy.

"Rin? Could you give me another demon king?"

He gave her a nervous smile, rubbing the back of his head. "Uhh, I'm not really sure…"

With a light shake of her head, she walked to his desk. Taking his textbook in hand, she opened to the page containing information on the topic they were discussing. Placing the opened text in front of him for him to look over, she gazed back to her class. "As Mr Okumura tries to find the last demon king, can someone give me the second last?"

Bon rose from his seat once more. "Samael, the King of Space of Time."

"Thank you, Mr Suguro. I'm quite happy to know I have such a brilliant student. Now, Rin, could you give us the last one?" she asked as she turned round and stepped towards the blackboard.

"Uhh," he scrambled with the book in front of him, reading directly from it, "_'Belial is the first of the Baal…known as the King of Evil and sometimes the prince of darkness and worth.'_"

The white-haired demoness nodded once more, inwardly smiling at the little secret she held. "Thank you. Glad to know that _most_ of you are aware of that basic information. Now, then," she started with a smirk, "let's get started!"

* * *

**Thank you!: **_**Mayumi Uchiha; DoveMusic; PhoenixBreaker90; kaysergizmo**_

**There's a link to a picture of Belial and Mephisto in my profile! :)**


End file.
